Understanding 80% Lowers: Everything You Need to Know

The world of firearms has always been filled with innovations and technological advancements. One of the most interesting and controversial topics in this world is the use of 80% lowers. Whether you’re a firearm enthusiast, a hobbyist, or someone looking to build their own firearm, understanding what an 80% lower is, how it works, and the legalities surrounding it is crucial.
This comprehensive guide will delve deep into the concept of 80% lowers, their usage, the steps involved in completing one, and the implications surrounding the legality of using or manufacturing them. Let’s explore the subject in detail.
What is an 80% Lower?
An 80% lower is essentially a partially completed lower receiver for firearms, most commonly associated with AR-15 or AR-10 style rifles. It is referred to as “80%” because it is only 80% complete, with the remaining 20% of machining required to turn it into a fully functional lower receiver.
To understand this, let’s break down the key components involved:
- Lower Receiver: This is the part of the firearm that houses the trigger mechanism, magazine well, and the other essential components. It is one of the most regulated parts of a firearm, as it contains the serial number that makes it traceable to the owner.
- 80% Lower: The term “80%” refers to a receiver that has been partially machined, leaving roughly 20% of the material to be removed. This remaining machining typically includes drilling holes, cutting the trigger pocket, and finishing the various contours and shapes that are needed to house other firearm components.
The idea behind 80% lowers is that they allow individuals to complete the firearm assembly without violating certain regulations that apply to fully functional receivers.
Legal Background of 80% Lowers
The legal status of 80% lowers has been a point of contention in the United States for years. Federal law prohibits the manufacture of firearms without a serial number, but the key is that an 80% lower is not considered a firearm under federal law until it is completed.
Under federal law, as defined by the Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF), an 80% lower is not classified as a firearm until it has been completed into a functioning lower receiver. This means that purchasing and owning an 80% lower is generally legal, provided it is not yet functional and does not contain the necessary components to operate a firearm.
However, once the lower receiver is completed and functional, it is considered a firearm and must be serialized. The individual who completes the firearm is responsible for ensuring that the firearm complies with local, state, and federal laws, including any laws related to registration and serial numbering.
Why Do People Choose to Build with 80% Lowers?
Building a firearm using an 80% lower has become increasingly popular among firearm enthusiasts, hobbyists, and even those interested in self-reliance. There are several reasons why people might choose to complete an 80% lower rather than buying a fully assembled lower receiver:
- Customization: When building a firearm from scratch, individuals can choose every single component, from the lower receiver to the upper receiver, the barrel, the stock, and everything in between. This allows for greater flexibility and customization compared to purchasing pre-assembled firearms.
- Cost Savings: Sometimes, completing an 80% lower can be cheaper than buying a pre-assembled lower receiver. The upfront cost of an 80% lower is usually less than the cost of a fully completed lower. However, one must factor in the cost of tools and equipment needed to finish the lower.
- Satisfaction of Building: For many firearm enthusiasts, there is a sense of pride and satisfaction in building a firearm from the ground up. The process of completing an 80% lower and assembling the various parts into a functional firearm can be a rewarding experience.
- Legal Advantages: In some areas, buying an 80% lower receiver can be a way to legally build a firearm without undergoing certain background checks or paperwork. However, this is only true as long as the lower receiver remains incomplete.
- Privacy: Some individuals prefer to build their own firearms as a way of maintaining their privacy. Since the completed firearm does not have to be registered in certain jurisdictions, building one from an 80% lower might allow the builder to avoid certain tracking or regulatory processes.
Steps Involved in Completing an 80% Lower
Completing an 80% lower is not an overly complicated process, but it does require some skill, tools, and attention to detail. Here’s a general breakdown of the steps involved in completing an 80% lower:
1. Acquire the Necessary Tools and Equipment
To begin, you’ll need several tools to finish an 80% lower. These include:
- A drill press or milling machine (a drill press is commonly used for AR-15 80% lowers).
- End mills (for cutting the trigger pocket).
- Drill bits (for drilling holes for pins and the trigger group).
- A jig (a device that holds the 80% lower in place and helps guide the cutting tools accurately).
2. Set Up Your 80% Lower in the Jig
The first step in the actual machining process is setting the 80% lower receiver into the jig. The jig ensures that all the necessary cuts are made in the right places and that the process is both accurate and safe.
3. Drill the Pin Holes
Start by drilling the necessary holes for the trigger pin, hammer pin, and other components of the lower receiver. These holes must be drilled precisely to allow for proper functioning of the firearm.
4. Cut the Fire Control Pocket
Next, you will need to mill out the fire control pocket (also known as the trigger pocket). This step is crucial, as it allows the trigger mechanism to fit properly. You will need to use a milling machine or a high-quality drill press with the appropriate cutting tools.
5. Smooth the Edges and Finish the Receiver
Once the critical cuts are made, you will need to smooth the edges and finish the receiver. This may involve filing or sanding down the edges to remove any burrs or rough spots left from the cutting process.
6. Inspect for Fit and Function
Before you proceed to assemble the rest of the firearm, it’s important to inspect the completed lower to ensure that all the parts fit properly and that the machining is correct. This may include testing the trigger mechanism, checking alignment, and making sure all holes are drilled accurately.
Completing the Build: Assembling the Lower Receiver
Once the 80% lower has been finished, you can begin the process of assembling the lower receiver. This involves installing components like the trigger, hammer, safety selector, magazine catch, and buffer tube. This step is relatively straightforward and can usually be done with basic tools.
The Legal Implications of 80% Lowers
While building a firearm from an 80% lower can be a legal activity under federal law, there are several important legal considerations to keep in mind:
- State and Local Laws: While federal law may not consider an 80% lower to be a firearm, state and local laws vary. Some states have stricter regulations, and it’s important to understand the laws in your jurisdiction before purchasing or completing an 80% lower.
- Manufacturing a Firearm: Under federal law, if you complete an 80% lower into a fully functional firearm, you are considered the manufacturer of that firearm. This means you are not required to put a serial number on the firearm unless you plan to sell it. However, it is advisable to place a serial number on your homemade firearm for identification purposes.
- No Commercial Sale: Federal law prohibits the commercial sale of firearms without a serial number. If you build a firearm from an 80% lower, it must be for personal use. Selling firearms made from 80% lowers without the proper licenses is illegal.
- ATF Regulation: The Bureau of Alcohol, Tobacco, Firearms, and Explosives (ATF) has regulations surrounding the sale and manufacture of firearms. While completing an 80% lower is legal, it is important to stay informed of any changes to regulations that may impact the process.
Common Myths About 80% Lowers
There are a number of myths and misconceptions about 80% lowers. Let’s address some of the most common ones:
- Myth: 80% Lowers Are Illegal: As long as you are completing the lower receiver yourself for personal use and not selling it, 80% lowers are legal under federal law.
- Myth: You Don’t Need a Background Check: While you do not need a background check to purchase an 80% lower, you will need one if you are purchasing completed firearm components, including a fully functional lower receiver.
- Myth: Completing an 80% Lower is Easy: While it’s certainly achievable for most people with the right tools and knowledge, completing an 80% lower does require technical skill, careful attention to detail, and access to specialized equipment.
Conclusion
Building a firearm from an 80% lower can be a rewarding project for those with the necessary skills and tools. Not only does it allow for a higher degree of customization and personalization, but it also provides a sense of satisfaction that comes from building something with your own hands. However, it’s essential to keep in mind the legalities and responsibilities that come with completing an 80% lower.
Whether you’re a hobbyist looking to experiment or an experienced firearm builder, understanding the process of completing an 80% lower is crucial. Stay informed, stay legal, and enjoy the process of creating your own custom-built firearm.